Issue #9: implement worker frame protocol

2026-04-26 16:20:16 -04:00
parent 41ddd122a6
commit a5098e6815
9 changed files with 511 additions and 0 deletions
@@ -0,0 +1,48 @@
+using System.Buffers.Binary;
+using Google.Protobuf;
+using MxGateway.Contracts.Proto;
+
+namespace MxGateway.Server.Workers;
+
+public sealed class WorkerFrameWriter
+{
+    private readonly WorkerFrameProtocolOptions _options;
+    private readonly Stream _stream;
+
+    public WorkerFrameWriter(
+        Stream stream,
+        WorkerFrameProtocolOptions options)
+    {
+        _stream = stream ?? throw new ArgumentNullException(nameof(stream));
+        _options = options ?? throw new ArgumentNullException(nameof(options));
+    }
+
+    public async ValueTask WriteAsync(
+        WorkerEnvelope envelope,
+        CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(envelope);
+        WorkerEnvelopeValidator.Validate(envelope, _options);
+
+        int payloadLength = envelope.CalculateSize();
+        if (payloadLength == 0)
+        {
+            throw new WorkerFrameProtocolException(
+                WorkerFrameProtocolErrorCode.InvalidEnvelope,
+                "Worker envelope cannot serialize to an empty payload.");
+        }
+
+        if (payloadLength > _options.MaxMessageBytes)
+        {
+            throw new WorkerFrameProtocolException(
+                WorkerFrameProtocolErrorCode.MessageTooLarge,
+                $"Worker envelope payload length {payloadLength} exceeds the configured maximum of {_options.MaxMessageBytes} bytes.");
+        }
+
+        byte[] lengthPrefix = new byte[sizeof(uint)];
+        BinaryPrimitives.WriteUInt32LittleEndian(lengthPrefix, (uint)payloadLength);
+
+        await _stream.WriteAsync(lengthPrefix, cancellationToken).ConfigureAwait(false);
+        await _stream.WriteAsync(envelope.ToByteArray(), cancellationToken).ConfigureAwait(false);
+    }
+}